NFL Wild Card Weekend game in San Francisco under threat from atmospheric river

The weather forecast for Saturday’s NFC Wild Card game between the San Francisco 49ers and Seattle Seahawks calls for heavy rain and strong winds. How will the grass at Levi's Stadium hold up?

A barrage of atmospheric rivers has dumped heavy amounts of rain across California over the past couple of weeks, and that will continue into this weekend.

The weather forecast for Saturday’s NFC Wild Card game between the San Francisco 49ers and Seattle Seahawks calls for heavy rain and strong winds. 

But with weeks of rain already, how is the field at 49ers’ Levi’s Stadium in Santa Clara, California, holding up? 

Well, we may not know until game time, but we spoke with West Coast Turf, whom the 49ers contract for their playing surfaces, to see what could expect. 

The San Francisco 49ers use a real grass playing surface, a Bermuda and Perennial Ryegrass mixture, at Levi's Stadium, and new grass was just recently installed on December 15. 

So, the 49ers have only played in two games on the new grass, but Greg Dunn with West Coast Turf said the grounds crew will do whatever is necessary to protect the field, including putting waterproof turf blankets on the field for the heavy rain forecast for Saturday. 

"They'll do that right up until Saturday… They'll keep the field under a waterproof tarp as close to game time as possible. So the field will likely only be rained on if they get rain on Saturday, pregame and during the game," said Dunn. 

Dunn said the field should be in great condition because it has only been played on twice and is not being used other than on game day. 

During Week 1 of the NFL season, we saw the new grass at Soldier Field when the 49ers took on the Bears was no match for the excessive rain they received. 

Grounds crews at Soldier Field were forced to push the water off the field with a squeegee throughout the game.

And even though the excessive rain was no match for the Bears' new turf, the puddles made for the perfect slip-n-slide for Chicago to celebrate their win over San Francisco.  

Dunn suggested that shouldn't be a problem at Levi's Stadium since all their root zone is what they call ‘USGA sand.’ 

"It's an engineered soil, and it's similar to a putting green on a golf course. So it has a very high infiltration rate, meaning water can go into it quite quickly," said Dunn. "So the root zone at Levi's stadium is an engineered root zone where there is no silts or clay or small particles. So the water infiltration rate is quite high." 

The natural-grass field at Levi’s Stadium hasn't always been in the headlines for good reasons. 

When the stadium opened in 2014, it got re-sodded after a week, because field conditions weren’t up to par during the preseason, and most recently, in November 2018, lots of slippage happened during a 49ers-New York Giants game. 

The Seattle Seahawks will take on the San Francisco 49ers at 1:30 p.m. PT on FOX. 


Debate between artificial turf vs. real grass 

The debate between playing on natural grass or artificial turf is nothing new in the NFL. 

However, it was brought back to the forefront after a string of injuries during a Week 7 game between the Seattle Seahawks and Los Angeles Chargers at SoFi Stadium

A study by University Hospitals Sports Medicine Institute analyzed data to compare injury rates on artificial versus natural playing surfaces among high school athletes – both male and female – for all sports played on a field. 

"They found athletes were 58 percent more likely to sustain an injury during athletic activity on artificial turf. Injury rates were significantly higher for football," the sports medicine institute stated. "Lower extremity, upper extremity, and torso injuries were also found to occur with a higher incidence on artificial turf."

Authors of previous studies found an increased rate of ACL injury in football athletes playing on artificial turf compared with natural grass, the study added. 

Doctors say that even though the quality of artificial turf has improved dramatically over the past years, these studies suggest athletes should take preventative measures when playing on artificial turf.

NFL Players Association President JC Tretter has called for all teams to use grass fields to reduce the risk of injury to players back in September 2020. 

Tretter cited NFL injury data from 2012 to 2018 that showed a 28% higher rate of non-contact lower-extremity injuries on artificial turf as compared to grass. He also noted of those non-contact injuries, players have a 32% higher rate of non-contact knee injuries on turf and a staggering 69% higher rate of non-contact foot/ankle injuries on turf compared to grass.

The stance from Tretter and other NFL players is that artificial turf is significantly harder on the body than grass. 

How many NFL stadiums have real grass?

Sixteen NFL stadiums have real grass. Ten of them have Bermuda grass, three have Kentucky bluegrass, two have Desso Grassmaster, and one has a combination of different grasses. 

GameOnGrass (GOG) has become a recently popular choice for those teams looking to have Bermuda grass.

"GOG is a sand-based sod grown on plastic, which creates an intense root mass and unparalleled durability," said Chad Price, owner of Carolina Green Corp.

The combination of the thickness and weight, and the intense root system from plastic grown, allow GOG to be laid and played on immediately.

GOG is currently on five NFL surfaces: Chicago, Baltimore, Washington, Kansas City, and Tennessee.

How many NFL stadiums have artificial turf?

Sixteen NFL teams play home games on artificial turf across 14 stadiums. The Giants and Jets share a turf field in MetLife Stadium, while the Rams and Chargers share a turf dome in SoFi Stadium. 

Which NFL stadiums have artificial turf, and which NFL teams have real grass?

Here is a full list of the playing surface for each NFL stadium: 

  • Arizona Cardinals State Farm Stadium: Bermuda grass
  • Atlanta Falcons: Mercedes-Benz Superdome: FieldTurf CORE
  • Baltimore Ravens M&T Bank Stadium: Bermuda grass
  • Buffalo Bills Highmark Stadium: A-Turf Titan
  • Carolina Panthers Bank of America Stadium: FieldTurf
  • Chicago Bears Soldier Field: Bermuda grass
  • Cincinnati Bengals Paycor Stadium: UBU Speed Series S5-M Synthetic Turf
  • Cleveland Browns FirstEnergy Stadium: Kentucky bluegrass
  • Dallas Cowboys AT&T Stadium: Hellas Matrix Turf
  • Denver Broncos Empower Field at Mile High: Kentucky bluegrass
  • Detroit Lions Ford Field: FieldTurf Classic HD
  • Green Bay Packers Lambeau Field: Desso GrassMaster
  • Houston Texans NRG Stadium: Hellas Matrix Turf
  • Indianapolis Colts Lucas Oil Stadium: Shaw Sports Momentum Pro
  • Jacksonville Jaguars TIAA Bank Field: Bermuda grass
  • Kansas City Chiefs GEHA Field at Arrowhead Stadium: Bermuda grass
  • Las Vegas Raiders Allegiant Stadium: Bermuda grass
  • Los Angeles Chargers SoFi Stadium: Hellas Matrix Turf
  • Los Angeles Rams SoFi Stadium: Hellas Matrix Turf
  • Miami Dolphins Hard Rock Stadium: Bermuda grass
  • Minnesota Vikings U.S. Bank Stadium: UBU Speed Series S5-M (turf)
  • New England Patriots Gillette Stadium: FieldTurf CORE
  • New Orleans Saints Caesar's Superdome: FieldTurf Revolution 360
  • New York Giants MetLife Stadium: UBU Sports Speed Series S5-M
  • New York Jets MetLife Stadium: UBU Sports Speed Series S5-M
  • Philadelphia Eagles Lincoln Financial Field: Desso GrassMaster
  • Pittsburgh Steelers Acrisure Stadium: Kentucky bluegrass
  • San Francisco 49ers Levi's Stadium: Bermuda grass and Perennial Ryegrass mixture
  • Seattle Seahawks Lumen Field: FieldTurf Revolution 360
  • Tampa Bay Buccaneers Raymond James Stadium: Bermuda grass
  • Tennessee Titans Nissan Stadium: Bermuda grass
  • Washington Commanders FedExField: Bermuda grass

There is no set rule for real grass versus turf, so it is up to each stadium to decide. 

Game prediction

When it comes to time to pick games, we never know how much of a factor weather can or will play. Usually, teams are picked because we believe they have better players, but what about picking a team solely based on how they have historically performed in certain weather conditions? 

Well, that’s what we can do, thanks to SportsWeather

SportsWeather has its own metrics system that compiles historical game-time weather data and meshes it against both NFL teams and player historical performance. 

It's forecast to feel like 58 degrees in San Francisco at game time on Saturday. At that temperature, historically, the 49ers are 50-52-1 and the Seahawks are 55-42.

Winds are expected to be blowing at 10 mph and over the last 15 seasons, San Francisco stands at 20-24-1 while the Seahawks are 24-11 when winds are blowing at that speed.

There is a 70% chance of rain on Saturday when the game starts. When that happens, the Seahawks stand at 14-8 and the 49ers come in at 10-4. 

PICK: gives the 49ers the major weather edge and predicts them to defeat the Seahawks in the Wild Card round.

Be sure to check back with SportsWeather on game day as weather can be unpredictable and may change from the current forecast.